My Tsubaki Omega O-ring chain came with a master link, and if I remember correctly, it was actually packaged in the plastic that contained the chain. This leads me to believe that they all come from the factory with the master link.
Just a suggestion for removing the 46mm bolt: buy a steel pipe. I spent an afternoon smacking the socket wrench, heating up the bolt with a blowtorch, and sweating to the point of nausea without the bolt budging. Finally I took my socket wrench to Home Depot, found a 5ft steel pipe that it fit into snugly, and bought it. Once I used that as a breaker bar, the bolt finally gave up with a satisfying groan.